Electron microscopic observations on the demanian system of female <i>Metoncholaimus denticaudatus</i> Schuurmans Stekhoven and Adam, 1931 (Nematoda)

Electron microscopic observations on the demanian system of female Metoncholaimus denticaudatus Schuurmans Stekhoven and Adam, 1931 from the Sluice Dock of Ostend lead to following conclusions: 1) there is no ductus uterinus; 2) the system is not a seminal receptacle; 3) it should be interpreted as an elaborate cascade system of glands, the secretion of which serves some important purpose related to reproduction

Evolution of the CERN Power Converter Function Generator/Controller for Operation in Fast Cycling Accelerators

Power converters in the LHC are controlled by the second generation of an embedded computer known as a Function Generator/Controller (FGC2). Following the success of this control system, new power converter installations at CERN will be based around an evolution of the design – a third generation called FGC3. The FGC3 will initially be used in the PS Booster and Linac4. This paper compares the hardware of the two generations of FGC and details the decisions made during the design of the FGC3

Is er leven na Kyoto?

A

New Method for Magnet Protection Systems Based on a Direct Current Derivative Sensor

A new method of the quench detection systems (QDS) designed for the LHC 600 A corrector magnet circuits and 6 kA individual powered quadrupole (IPQ) magnet circuits is presented. In order to improve the dependability of QDS, a direct measurement of the current derivative is proposed. The quench detection scheme for the 600 A corrector magnet circuits uses the current derivative numerically evaluated from a direct current measurement. In order to make the calculation stable, the current derivative is heavily filtered, thus introducing a significant phase shift, which restricts the operational range of circuit parameters such as the acceleration. For the 6-kA IPQ magnet circuits the main quench detection is based on a classical bridge configuration. The introduction of an additional detection channel for the direct measurement of the current derivative helps to overcome the lack of sensitivity to fully aperture symmetric quenches of the bridge configuration. Transformer-based current derivative sensors are currently under development, using cut cores for easy prototyping, performance control, and installation. Prototypes for the ±600 A current range and ramp rates between 0.1 and 5 A/s were built using different core materials (electrical steel and nanocrystalline cores) and pickup coils with 10 000 and 20 000 windings. In order to characterize the prototypes, the performance was defined in terms of mean sensitivity of the sensor response in [V/A/s] and the performance quality factor (PQF), defined as a percentage of nonlinearity of the response. An optimization procedure was implemented for finding the best configuration of the sensors, i.e., the air gap in the cut core in order to maximize the mean sensitivity and to minimize the PQF. The tests were carried out at different working points (current ranges and ramp rates) showing promising results (PQF <0.5% with a sensitivity of 5.5 mV/A/s)

La politique européenne de cohésion économique et sociale et l'avenir des zones rurales fragiles : le cas de la Bretagne

Cette communication examine les fondements politiques, économiques et éthiques de la politique européenne de cohésion économique et sociale, dont font partie les interventions en faveur du développement rural. Elle tente une évaluation des effets de cette dernière politique en Bretagne. Les résultats de cette évaluation sont ambigüs, le rôle des programmes d'aide ne pouvant être clairement mis en évidence

Powering Tests and Magnet Training

In this paper the powering tests and magnet training during the hardware commissioning campaigns of Run 2 are discussed, and the implications of running at 7 TeV from a magnet training and reliability perspective are given. During Run 2, the efficiency of powering tests has steadily increased due to enhanced control software, more automatic analysis, and more experienced CERN personnel. The MP3 Intervention Matrix, used for documenting requalification procedures after interventions, is presented. Given that the main dipole circuits are considered the main bottleneck for reaching 7 TeV operation from a magnet training perspective, training of these circuits is discussed in detail with regards to training efficiency and electrical integrity. The training campaign of December 2018 comprised training of the main dipole circuit in sector 12, all main quadrupole circuits, the individually powered dipoles and quadrupoles, and the inner triplets of points 1 and 5. Due to time constraints, the training targets were only partially reached. In general the observed training behavior was encouraging, although training on the main dipole circuit in sector 12 was slower than expected. Also considering that all dipoles have previously reached a quench current of at least 12 kA before installation into the LHC, no showstopper was identified for reaching 7 TeV operation. With regards to reliability of magnet operation at 7 TeV, no problems are expected in terms of flattop quenches, but the sensitivity to UFO-induced quenches is expected to increase significantly